<?php
class JSSDK {
  private $appId;
  private $appSecret;

  public function __construct($appId, $appSecret) {
    $this->appId = $appId;
    $this->appSecret = $appSecret;
  }

  public function getSignPackage() {
    $jsapiTicket = $this->getJsApiTicket();

    // 注意 URL 一定要动态获取，不能 hardcode.
    $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
    $url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

    $timestamp = time();
    $nonceStr = $this->createNonceStr();

    // 这里参数的顺序要按照 key 值 ASCII 码升序排序
    $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";

    $signature = sha1($string);

    $signPackage = array(
      "appId"     => $this->appId,
      "nonceStr"  => $nonceStr,
      "timestamp" => $timestamp,
      "url"       => $url,
      "signature" => $signature,
      "rawString" => $string
    );
    return $signPackage; 
  }

  private function createNonceStr($length = 16) {
    $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    $str = "";
    for ($i = 0; $i < $length; $i++) {
      $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
    }
    return $str;
  }

  private function getJsApiTicket() {
     if (IMS_VERSION >= 0.6) {

            load()->func('cache');

        }

        $api = cache_load("ewei.comeon.api_share.json::".$this->weid, true);

        $new = false;

        if(empty($api['appid']) || $api['appid']!==$this->appId){

            $new = true;

        }

        if(empty($api['appsecret']) || $api['appsecret']!==$this->appSecret){

            $new = true;

        }

        

        $data = cache_load("ewei.comeon.jsapi_ticket.json::".$this->weid, true);



        if (empty($data['expire_time']) || $data['expire_time'] < time() || $new) {

            $accessToken = $this->getAccessToken();

          

            $url = "http://api.weixin.qq.com/cgi-bin/ticket/getticket?type=1&access_token=$accessToken";

            $res = json_decode($this->httpGet($url));

            $ticket = $res->ticket;

            if ($ticket) {

                $data['expire_time'] = time() + 7000;

                $data['jsapi_ticket'] = $ticket;

                cache_write("ewei.comeon.jsapi_ticket.json::".$this->weid, iserializer($data));

                cache_write("ewei.comeon.api_share.json::".$this->weid, iserializer(array("appid"=>$this->appId,"appsecret"=>$this->appSecret)));

            }

        } else {

            $ticket = $data['jsapi_ticket'];

        }



        return $ticket;
  }

  private function getAccessToken() {
	   if (IMS_VERSION >= 0.6) {

            load()->func('cache');

        }

		$api = cache_load("ewei.comeon.api_share.json::".$this->weid, true);

        $new = false;

        if(empty($api['appid']) || $api['appid']!==$this->appId){

            $new = true;

        }

        if(empty($api['appsecret']) || $api['appsecret']!==$this->appSecret){

            $new = true;

        }

        

        $data = cache_load("ewei.comeon.access_token.json::".$this->weid, true);

     

        if (empty($data['expire_time']) || $data['expire_time'] < time() || $new) {

            $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";

            $res = json_decode($this->httpGet($url));

            $access_token = $res->access_token;

            if ($access_token) {

                $data['expire_time'] = time() + 7000;

                $data['access_token'] = $access_token;

                cache_write("ewei.comeon.access_token.json::".$this->weid, iserializer($data));

                cache_write("ewei.comeon.api_share.json::".$this->weid, iserializer(array("appid"=>$this->appId,"appsecret"=>$this->appSecret)));

            }

        } else {

            $access_token = $data['access_token'];

        }

        return $access_token;
  }

  private function httpGet($url) {
    $curl = curl_init();
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_TIMEOUT, 500);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
    curl_setopt($curl, CURLOPT_URL, $url);

    $res = curl_exec($curl);
    curl_close($curl);

    return $res;
  }
}

